|
|
|
| Registros recuperados: 18 | |
|
|
| Lopes,Toni Jefferson; Gonçalves,Odinei Hess; Barros,Ricardo Barbosa; Capelli,Francine Carla Rodrigues; Machado,Ricardo Antonio Francisco; Quadri,Mara Gabriela Novy; Quadri,Marintho Bastos. |
| The main purpose of this work was to produce a pellet to minimize undesirable effects in fixed beds, such as colmatation, through clay fixation on the surface of polymeric particles. Preliminary experiments were carried out by heating the clay, namely Tonsil Terrana 580FF, in order to observe variations on its capacity to adsorb anthocyanins derived from red cabbage. Clays was fixed on five samples of high density polyethylene (HDPE) at 180°C -210°C for two hours. The morphological analyses of the resulting particles were accomplished through Scanning Electron Microscopy (SEM). The experiments demonstrated an increase on clay's adsorptive capacity of 15.65% at 120°C for 30 hours and 16.80% at 170°C for two hours. The SEM analysis showed that the clay... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adsorption; Clay; Polymer; Anthocyanin/red cabbage. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000400034 |
| |
|
| |
|
| |
|
| |
|
|
| Adekola, Kehinde Adedeji. |
| Termite hills are described as the structure built by termite using soil in the surrounding or within the earth. The mound has extremely hard walls constructed from bits of soil cemented with saliva and baked by the sun. This research is to determine the compressive strength of termite hill soil stabilized with rice husk. The study investigated the compressive strength of 150 mm x 150 mm x 150 mm cubes made from termite hill soil and rice husk in the different mix ratio of 50:50, 60:40, 70:30, 80:20, 100:0 and was cured for 28 d with crushing the cubes at 7 d interval. The weight, bulk density and dry density of the cubes at different THS/RH mix ratio ages were determined. Test results showed that the compressive strength of the cubes increases with age... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Termite hill soil; Clay; Rice husk; Compressive strength; Cubes; Structure; Farm; Nigeria. |
| Ano: 2016 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3398 |
| |
|
|
| Levy,Camila de Carvalho Braga; Mellis,Estêvão Vicari; Murrer,Marina Krey; Inglés,Carlos Repiso; Daynes,Cathal N.; Cavalli,Edilson; Chiba,Marcio Koiti. |
| ABSTRACT Although nickel (Ni) is recognized as plant nutrient since the turn of the 21st century, uncertainty remains about its optimum application rates and forms. This paper focuses on Ni application in soils, relating to its effect as a plant micronutrient. Specifically, the effect of Ni on the activity of urease in soybean plants is examined. The effects of applying four Ni rates in two different soil types were tested. A full factorial 2 × 4 blocked design experiment was established under controlled conditions. Ni rates (0, 0.25, 0.5 and1.0 mg of Ni·kg–1 of soil) were applied in two soils with contrasting clay contents. The addition of Ni increased the urease activity in soybean plants but was affected by soil textural differences. The highest urease... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Urease; Clay; Sand; Oxisol; Glycine max. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052019000300432 |
| |
|
|
| Jacobs, Walter; Le Hir, Pierre; Van Kesteren, Walther; Cann, Philippe. |
| Results of a large number of erosion tests on artificially generated and relatively dense sand-mud mixtures are presented. Soil sample compositions are varied concerning clay-silt and sand-silt ratio, and clay mineralogy. The experimental set-up consists of a re-circulating small-scale rectangular erosion flume with unidirectional flow conditions. The erosion threshold and erosion rate are studied through step by step increasing the flow rate during a test. Results clearly indicate time-decreasing erosion during which individual flocs are randomly eroded, and time-independent (steady) erosion during which both sand and mud particles are continuously and uniformly eroded. These two erosion types appear to be floc and surface erosion, respectively... |
| Tipo: Text |
Palavras-chave: Erosion; Sand-mud mixtures; Clay; Sediment structure; Critical shear stress; Strength. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15252/12678.pdf |
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
| Halloran, Paul R.; Rust, Nigel; Rickaby, Rosalind E. M.. |
| Trace element analysis of open-marine sedimentary carbonates provides a wealth of paleoclimate data. At present, the majority of this data is obtained from foraminifera tests. Complications regarding the variability of conditions experienced by foraminifera throughout test formation and the influence of diagenetic processes on sample chemistry limit the value of foraminifera samples in certain situations. Coccoliths, the calcium carbonate plates produced by coccolithophores, represent a second major pelagic open-marine carbonate source with the potential to provide a wide range of valuable trace element proxy data but which have, until now, been unavailable for analysis of many trace elements because of clay contamination. Here we describe a novel... |
| Tipo: Text |
Palavras-chave: Coccolith; Coccolithophore; Clay; Sorting; Trace element; Geochemistry. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00220/33080/31542.pdf |
| |
|
|
| Lemos,Marina Jorge de; Calixto,Lígia Fátima Lima; Alves,Osvanira dos Santos; Souza,Daniele Santos de; Moura,Bárbara Brandt; Reis,Túlio Leite. |
| The objective of this study was to evaluate the effect of the addition of kaolin in the diet on performance, litter moisture and intestinal morphology of broiler chickens. Four hundred ninety-two broiler chickens distributed in a completely randomized design with three treatments and four replicates of 41 birds each, divided into three periods (15-21; 22-34; 35-52 days) were used. The following treatments were: Control - reference diet without added kaolin; treatment 1 - reference diet + 0.75% kaolin; Treatment 2 - reference diet + 1.5% kaolin. The variables analyzed were: feed intake, average weight, average weight gain, feed conversion, litter moisture, villus height and crypt depth. The inclusion of kaolin in the diet significantly reduced feed intake,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Clay; Feed conversion; Intestinal villi.. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015001001835 |
| |
|
|
| Combatt-Caballero,Enrique Miguel; Palencia-L,Manuel; Borja-M.,Katerine. |
| Abstract The aim of this study was to evaluate the Bouyoucos method, at different stirring times and using two chemical dispersants, for particle size determination and distribution in slightly alkaline soils of Córdoba, Colombia. Eight soils were mechanically dispersed applying a slow stirring; 60 rpm with five stirring times as follows: 2, 4, 6, 10 and 16 hours and a control experiment at 0 h. Chemical dispersion of samples was performed using two dispersants: Calgon (0.058 molL-1 (NaPO3)6 + 0.075 molL-1 Na2CO3) and a mixture of Calgon and 0.1 molL-1 Na4P2O7 at pH 9.1, which was proposed by authors. In addition, particle size distribution was determined by Pipette method, which was used as reference method. Tests of means and regression models were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stirring; Clay; Sand; Chemical dispersants; Silt; Texture; Timing. |
| Ano: 2018 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-28122018000100126 |
| |
|
|
| Tito,Gilvanise A.; Chaves,Lucia H. G.; Guerra,Hugo O. C.; Soares,Frederico A. L.. |
| The objective of this study was to determine the effect of zinc, copper and cadmium on phytomass and grain production and to evaluate indirectly the adsorbent effect of bentonite clay by determining the accumulation of these heavy metals in bean plants. The study consisted of three separate experiments (one for each cation) with the application of three doses of bentonite (0, 30 and 60 t ha-1) in pots containing separately 50 mg of Zn; Cu and Cd kg-1 of soil, with three replicates. Thus, each experiment consisted of 9 experimental units. In each one, a bean plant was cultivated and after 65 days, samples of leaves, stems, roots and grains were collected. Afterwards, the samples were dried, weighed, grinded and the concentrations of Zn, Cu and Cd were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metal; Clay; Vigna unguiculata L.. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662011000700003 |
| |
|
|
| Chiba, Marcio Koiti; IAC; Natale, William; UNESP; Cruz, Mara Cristina Pessôa da; UNESP; Teixeira, Luiz Antonio Junqueira; IAC; Centurion, José Frederico; UNESP. |
| Este trabalho teve por objetivo estudar a distribuição de formas não-trocáveis de potássio, em frações texturais de um Latossolo cultivado com bananeira, por dois anos, em dois regimes hídricos (parcelas principais), e doses de potássio (0, 300, 600 e 900 kg há-1) (subparcelas), seguindo delineamento em blocos casualizados, com parcelas subdivididas. Verificou-se que os maiores teores de potássio (trocável e não-trocável) estão contidos nas frações mais finas: argila e silte. Neste sistema de cultivo e com a aplicação dos adubos na superfície, a movimentação do nutriente, nas camadas estudadas, esteve associada à presença e movimentação da água no perfil do solo. A irrigação desempenhou papel relevante na distribuição das formas do K. Nas parcelas... |
|
Palavras-chave: 5.01.00.00-9 Agronomia irrigação; Argila; Silte; Areia; K-trocável; K não-trocável. irrigation; Clay; Silt; Sand; Exchangeable K; Non-exchangeable K. |
| Ano: 2008 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5321 |
| |
|
|
| Tavares,Rose Luiza Moraes; Oliveira,Stanley Robson de Medeiros; Barros,Flávio Margarito Martins de; Farhate,Camila Viana Vieira; Souza,Zigomar Menezes de; Scala Junior,Newton La. |
| ABSTRACT: The Random Forest algorithm is a data mining technique used for classifying attributes in order of importance to explain the variation in an attribute-target, as soil CO2 flux. This study aimed to identify prediction of soil CO2 flux variables in management systems of sugarcane through the machine-learning algorithm called Random Forest. Two different management areas of sugarcane in the state of São Paulo, Brazil, were selected: burned and green. In each area, we assembled a sampling grid with 81 georeferenced points to assess soil CO2 flux through automated portable soil gas chamber with measuring spectroscopy in the infrared during the dry season of 2011 and the rainy season of 2012. In addition, we sampled the soil to evaluate physical,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Saccharum officinarum; Soil respiration; Green sugarcane; Clay. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000400281 |
| |
| Registros recuperados: 18 | |
|
|
|
